I installed iOS 6.1.3 a couple of days back and my iPhone began heating up like crazy and started running out of charge in under 4 hours. I should have read this article, which may have saved me some of this trouble. Realizing something was wrong I tried Apple care as well as the Genius bar, both to no avail. Both had very helpful people, but the diagnosis was incomplete and didn’t solve my problem. This is a description of the problem and a temporary fix until Apple releases a real fix in an iOS 6.1.x release.

The symptoms:

1. Phone was heating up like crazy!

2. Battery lasted for < 4 hours without any apps open.

3. Standby time and Usage time were pretty much almost equal (~4 hours).

Anyway, I did a little bit of poking around on the phone and found that the cause of all the problems (atleast for my phone) was that the “dataaccessd” daemon was crashing over and over again. This is the daemon that manages keeping data in sync between the phone and web-servers such as iCloud or Google’s exchange servers. I’m guessing Apple may have modified how this data exchange is done to improve the sync with iCloud, but this may have resulted in it crashing on my phone when talking to other exchange servers that use Activesync.

Now, this made more sense – if the dataaccessd daemon keeps trying to access the internet to get to the exchange servers and crashing, and then re-spawning over and over again, the phone will have high CPU usage and possibly high RF-usage (depending on how far into the sync it got). I tried disabling all syncs first and found that this appeared to help the phone run a little cooler. I re-enabled iCloud and it seemed like this didn’t make the phone heat up again. Turning on my Gmail calendar exchange got the phone heating up again – so I decided that this Gmail calendar sync was the most likely suspect.

Right now as I write this the phone battery is still at 77% charge after 17 hours – Usage 2 hours, 15 mins; Standby 17 hours, 11 mins. Which means – this solves the power usage issue (atleast for me).

I’m guessing most people complaining about their iPhones/iPads running out of charge after an iOS 6.1 upgrade are probably having the same or a similar issue.

The temporary fix:

1. Go to “Settings” -> “Mail, Contacts, Calendars”.

2. Under “Accounts” turn off “Calendars” for everything other than iCloud. Do this especially for Gmail accounts. Note – the problem seems to be related only to Calendars, so don’t worry about syncing email and so on – that seems to be working well. 🙂

This should fix power consumption issues.

Unfortunately this doesn’t solve the root cause of the problem which appears to lie in iOS 6.1.3. Apple needs/will most likely release a fix for this soon – I do rely a lot on my Gmail calendars and this is inconvenient. That being said though everyone makes mistakes – there are times when even Apple is going to slip up. I just hope they fix this issue soon and are more careful with testing iOS updates, before releasing them in a hurry.

Update:

I don’t know if this is necessarily an issue on Apple’s end or if it is due to changes on the server side by Google (for eg.), because there are many people who are having similar issues with older versions of iOS 6.1. In terms of battery usage, this was certainly the problem for me. My phone is still doing great at: 28 hours standby, usage: 3 hours, 36 minutes and the phone still has 37% charge. Hopefully the party which has changed something with the sync mechanism will fix it soon and we can all get more mileage from our phone battery while still being productive.

One thin to keep in mind is that google, very recently, and very quietly changed the service for active sync and exchange servers on their end. They are basically saying that they no longer support imap exchange and want everyone to switch to caldav and carddav.

if you go to http://www.google.com/sync/index.html and look at the instructions for iphone, you will see that they changed. They did this some time back at the begenning of the year, however they would “honor” old accounts using exchange until some time in march/april. Well… looks like they might be turning off those accounts.

Try updating your google information as they have listed and see if that helps, worked for me.

I agree with your assessment that this is likely a Google issue. As for the fix though, I deleted my old gmail accounts from the phone and setup the sync again using the instructions from the link above. The accounts came back up, but so did the crashes and power consumption problems. Perhaps theres something I missed – will comb through the instructions more carefully tomorrow morning.

Thanks! This solved my problem, at least temporarily. For me it was the calendar app sync with iCloud. Since I turned it off things have been working well and the battery life is back to normal. Looking forward to a software update from Apple that will allow me to turn the calendar sync back on. In the meantime, though, this is a great fix. Thanks very much for posting–none if the other online suggestions had worked.

Hi! Thaaaaaaaanksss a LOTTTT!!! you has been really helpful for me, my iphone is now working smooth and its battery is lasting as it should… I have sharing your solution over the apple official forums so anyone could fix this annoying bug.